<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			.b{
				height: 100%;
				width: 100%;
				border: 1px solid;
			}
			.a{
				height: 100px;
				width: 100px;
			}
			.d{
				height: 100%;
			}
			.q{
				height: 100%;
				position: absolute;
			}
		</style>
	</head>
	<body>
		<div class="b">dsdad</div>
		<div class="a"><div class="d">sdad</div></div>
		<div class="q">sds</div>
		<script type="text/javascript">
			console.log(document.querySelector(".b").offsetHeight);//23
			console.log(document.querySelector(".d").offsetHeight);//100
			console.log(document.querySelector(".q").offsetHeight);//722
		</script>
	</body>
</html>
